Post on 30-Dec-2015
description
Objectives
• Discuss energy flow through different ecosystems
• Trace cycles of Carbon, Nitrogen, and water
Ecosystem
All the energetic interactions and material cycling that link organisms in a community with one another and with their environment
Laws of Thermodynamics
Energy is not created or destroyed. It changes form and place
When energy changes form some of it is lost as entropy (heat)
Production
Primary Production = energy accumulated by plants
Gross Primary Production = total photosynthesis
Net Primary Production = energy remaining after Respiration and stored as organic matter.
NPP=GPP-R
Standing crop biomass = accumulated organic matter on a given are at a given time
Difference in productivity
• Species efficiency• Efficiency = NPP/GPP• Corn .85• Deciduous trees .42• Prairie grass .66
• Physical environment– Water
– Heat
Secondary ProductionAnimals
Energy, once consumed goes to maintenance, and waste. Little is left for production.
10% rule .
Definitions
Food Chain– series of steps by which energy stored in plants is passed through an ecosystem
Fig. 5.14
Definitions
• Food web – several interrelated food chains
Fig. 5.15
Components
• Producers – plants
• Herbivores – convert plant tissue into animal tissue
• Carnivores – eat other animals, levels
• Omnivores – eats both plants and animals
Components
• Scavengers – animals that eat dead plant and animal matter
• Saprophytes – plant and fungi that absorb dead material
• Decomposers – everything is a decomposer
Another way of viewing energy relationships
(Heterotrophs)
Biophages – use living matter
Saprophages – use nonliving matter
Two Major Food Chains
• Grazing food chain – energy flows through the biophages
• Detrital food chain – energy flows through the saprophages.
Fig. 23.3
Fig. 23.4
Fig. 23.5